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Myth Busters/overdrive Bulbs

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gobie

dave the gobie
Joined
Dec 2, 2004
Messages
366
Location
Auburn
I decide to email the mythbusters at the discovery channel and asked them to look into overdriving flourescent bulbs to see if they do burn brighter. i figured that so many people keep doing posts on this subject that it would be a good myth to either prove or dispell. I figured that this would make for a great segment. I am hoping to hear back from them soon. :D
 

Boomer

RF Staff
Joined
Dec 15, 2004
Messages
2,774
Location
Duluth, Minnesota
I don't know where this myth comes from :lol:

Applying New Lighting Technologies

By Joseph R. Knisley, Senior Editorial Consultant, EC & M

That is these guys http://pirt.ecmweb.com/

About a year ago, Joseph Good III, President of the Illuminating Engineering Society of North America (IESNA), offered his view of what lighting would be like in the next two decades. He foresaw lighting systems that could adapt easily to changing needs of the user and function as a fully integrated system, rather than a collection of independent components.

These predictions are already coming true with today's exciting lighting technologies. Let's look at some of these technologies, which involve solid-state electronics, optical systems, and communications/control.

Making use of ballast factor. The wide-scale adoption of T8 linear fluorescent lamps and electronic ballasts is an ongoing phenomenon. Using solid-state components, electronic ballasts rectify the 60 Hz input and then invert it to create the 20,000 Hz to 60,000 Hz current, which operates the lamp. The higher frequency current of the arc stream causes greater phosphor excitement, providing more light output for a given ballast input power.

One of the biggest advantages of using electronic ballasts is the ability to consider the ballast factor (BF) in a design or specification. Though we weren't using the concept of the BF metric in the old electromagnetic ballasts era, we are today. Essentially, the BF is the ratio of light output from a commercial ballast compared to that obtained by a reference ballast, which has a BF of 1.

Thus, designers specify a BF of 0.88 to provide an equivalent light output when doing a one-to-one upgrade from T12 to T 8 lamps (that is, retaining the same number of lamps and fixtures).

At the same time, designers specify a BF of up to 1.2 for systems that produce too little light or in applications where they will reduce the number of lamps in a layout of linear fluorescent fixtures. So, in this case, the higher BF allows the lamps to provide up to 30% more light. This is similar to installing a four-barrel carburetor on a gasoline engine to deliver more power than a two-barrel design. It is possible to use up to a 1.2 BF without worrying about overdriving the lamps.

So he is making the lamps brighter without overdriving them and OD them they get even brighter, but then there is life loss

From an electrical engineer on RC

Hi,

Thanks for you questions and comments. Another long one...sorry.

There are several reasons why I used T8s instead of T12s. It is true that T12s are more availble than T8s at Home Depot. However in the construction business, T8s is practically the defacto standard. So, finding T8s is just a quick trip to a lighting store. Most stores don't give you any problems if you look like you know what you are doing BTW, you can use a T8 ballast to drive a T12 lamp. Most T12 lamps may not last as long because they are not design to be used with instant start -- but they will light. If you use lamps that are manufactured to be ISable, they should work fine.

T8s. They are more efficient (lumens/watt). Tthey are more environmentally friendly (less packaging, less materials used and etc). They are easier to direct intense lighting to a specific area -- less diffusion, like MH. Electronic ballasts are cheaper and easier to obtain for the T8 format. Put it this way, a 2x175W is as bright as 2x80W NOs....I just save myself 170Ws. Of course, I don't have the "heating" capabilities of the MH and the glitter lines.

End caps: The $3 endcaps that I have are rated for 600V @ 600W. The overdrive NOs are ~180V@80W -- so we are electrically safe. As for thermal, I don't think they will melt. 60 deg C water can be safely transport through PVC -- so, it should be a problem for the endcaps. My DIY reflector (white aluminum flashing) is touching the lamps and they are luke warm. You can use waterproof caps...but I think they are made from the same material...PVC (maybe hi temp PVC...I don't know). This is one of the reasons why I wanted to limit the overdrive to 90W...it would be a bit risky. In comparison, I have a 55W PC on another tank. And the PCs are much hotter than the OVRNO (overdrive NO). I can't touch my PCs for more than a second.

Lamp life: Well, they should be good for a year. I have seen any black ends on my tubes...yet. I have been using them for about three months now. At $3.50 CAD per tube, I don't mind replacing them every six months. Ballast life...should be okay too. The ballast is designed to drive 110W (or 4 lamps) and the heat dissipated from the ballast is a luke warm. Nothing smells funny, acts funny or sounds funny. No sparks. Perfectly...silent.


The Waiver:
I really didn't want to say it...but I also didn't want a lawsuit either. Basically, I feel it is safe and it is something worth pursuing for a DIY reefer (otherwise...I won't have posted it). Under the "for those who dare to try" section, you will notice that we start at 1x drive first. Run it for a while. Make sure the temperature of the ballast and tube are not too hot. The ballast is engineered to drive 1 tube (i.e. the other three tubes are blown). Then...try 2x. then 3x and finally 4x. You'll find that the 3x and 4x are starting to hit the diminishing returns mark.

The shorter tubes:

Actually...you can use them in series. The instant start mechanism should have enough oomth to strike both tubes. If not, you can try one tube....it won't burn it out. The T8 ballast is design to light 24", 36" and 48" T8s.

I understand your concerns. It sounds scary, but I am sure it will work. Most electronic ballasts should work -- besure its a F32T8 X 4 type (you'll know, they are the second cheapest kind).
- Victor.


More from RC

http://reefcentral.com/forums/showthread.php?s=&threadid=113004&highlight=t5
Hope that helps.

The info on OVRNO is endless on the net, to include images of OVRNO vs non-OVRNO, in relation to intensity/brightness
 
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